It is known to provide a pharmacologically active compound in finely divided particulate form for self administration by inhalation to relieve respiratory problems, particularly asthma.
Such compounds can be provided in containers, each of which has a number of compartments, each containing a respective dose of the compound. Such containers are used in conjunction with an inhaler which releases each dose of the compound in turn. For example, European Patent specification No EPO 211595 (Glaxo Group Limited) shows an inhaler in which particular material is administered from a disc-shaped blister pack.
The blisters of the disc are loaded with powder by means of a filling head which separates individual doses of compound from a reservoir and allows those doses to pour into the blisters. The inherent inaccuracies in the measurement of each dose, and the need to provide a powder with suitable flow characteristics to enable filling result in the compound having to be mixed with a significant amount of lactose.
This increases the required size of the individual blisters in the container, thus reducing the number of doses which can be dispensed from a container of a given size. In addition, the user, in self administering a dose of medicament, has to inhale a relatively large amount of powder which can give rise to an unpleasant sensation in the user's mouth and throat.